1. Field of the Invention
The present invention relates to a pneumatically actuated switching device in a pneumatic actuator system for a patient call system. More specifically, the present invention relates to an interchangeable snap fit air connector assembly for a pneumatically actuated switching device connected to a pneumatic actuator of a patient call system.
2. Description of the Prior Art
Hospitals, and other patient-care institutions, frequently provide patient call systems wherein a patient may activate a signal to a central station, such as a nurse's station, to summon assistance. The use of conventional electrical switches to generate the signal in such environments is undesirable given the potentially combustible levels of oxygen that will likely be present near the patient.
As an alternative to conventional electrical switches, the use of a pneumatically actuated switch, which utilizes a pulse of pressurized air to actuate a signal circuit, avoided the safety concerns associated with a conventional switch. Such switches are particularly beneficial where combustion concerns may be present, as in oxygen rich environments, because the construction of the pneumatically actuated switch limits the possibility of arcing which is a problem associated with electrical switching.
U.S. Pat. No. 3,823,285 to Dwyer illustrates an example of a pneumatic actuated bulb device for a patient actuated nurse call system. A deformable pneumatic bulb provides a source of pressurized air to operate an electrical switching circuit that is well suited for use in environments where it is undesirable to use a conventional electrical switch as discussed in the preceding paragraph. A pneumatically actuated switching device comprises an electrically conductive sleeve having a bore. An electrically conductive ball is mounted in the bore and is movable in response to the pneumatic pressure. The other end of the bore is in communication with a tube to which is connected a source of pneumatic pressure, such as the deformable pneumatic bulb. Two conductors are adapted to be connected to two sides of an electrical circuit. The first conductor is in electrical communication with the sleeve and the second conductor is mounted in an opening in the sleeve which extends into the bore. The ball is movable between a circuit open position out of electrical communication with the second conductor, and a circuit closed position in electrical communication with the second conductor and the sleeve. A cam surface extends into the bore and into the path of the ball and cams the ball into electrical communication with the second conductor and the sleeve in the circuit closed position. The sleeve normally is oriented generally vertically, although the device operates satisfactorily when the sleeve is oriented almost horizontally because the ball moves in the bore with very little, if any, friction.
A further development of a pressurizing device is disclosed in U.S. Pat. No. 5,155,309 which embodies a pneumatic bulb having an annular ring configuration with a convexly shaped actuator dome resembling a doughnut to provide a distinctive identification to the bulb for distinction from other pneumatic bulbs that may be utilized for different purposes in a patient area. The construction of the pneumatic bulb includes a base plate to provide support for the bulb and support for a peripheral rim and a center post of the doughnut shaped actuator dome. The base plate includes protruding truncated conical members relied upon to maintain the doughnut shaped actuator at a fixed location on a patient's mattress so that the patient can reliably find the bulb to summon help.
These pneumatically actuated patient call systems comprise an air tube for delivering compressed air for activation of the electrical connection of a jack which is inserted into a receptacle of a wall switch unit of a patient call system. The receptacle can be either recessed into or flushed with a wall plate wherein an air tube positioned at a right angle relative to the electrical connection may be better suited for use with a receptacle that is flushed with the wall plate and wherein an air tube positioned in-line (straight jack) relative to the electrical connection may be better suited for use with a receptacle that is recessed into the wall plate of the wall switching unit.
U.S. Pat. No. 5,736,702 to Roberts, et al. discloses a pneumatically actuated switching device with a housing connection which provides for optional assembly orientations, i.e. an in-line assembly configuration for the switch housing and a right angle configuration for the switch housing relative to a jack for electrical connection with the receptacle of a patient call system. The optional assembly orientations are brought about via a connector which is partially enclosed within a cavity formed in an end of the housing. The cavity of the housing includes opposing side walls and a curved surface located between the side walls. The contour of the curved surface is compatible with the surface of the connector such that the two components can be brought into interfacing contact with one another. In order to maintain the interfacing contact between the connector and the housing, pins extend through the connector and through the opposing side walls of the housing thereby locking the two components together in a preselected angular orientation of the connector relative to the housing. The additional openings in the sidewalls provide for the different angular orientation options for the connector during the assembly of the switch. End connectors form the final closure for maintaining the locked assembly orientation by retaining the pins within the openings in the connector and the housing. The connector and the housing of this multi-position switching device is generally glued together once the pins are in the appropriate openings for forming a desired angular orientation of the connector relative to the housing.
There is a need for a pneumatically actuated switching device for delivering pressurized air for an electrical connection that easily provides an air connector assembly for connection to a housing supporting the electrical connection and which air connector assembly may be selected to provide a desired angle, i.e. an in-line air conduit assembly or a right angle air conduit assembly configuration for the switch housing relative to the electrical connection depending on the type of receptacle in the wall switch unit receiving the electrical connection.